body {
    background-image: url(bg.jpg);
}
header {
    display: block;
    width:600px;
    margin: 0 auto;
    font-family: Arial, serif;
    padding-left: 100px;
}
header h1 {
    width: 500px;
    font-size: 60px;
    text-align: center;
    margin-bottom: 0px;
}
header p{
    font-size: 25px;
    margin: 20px auto;
}
header #newgamebtn {
    width: 100px;
    padding: 10px 10px;
    color: white;
    background-color: #8ade7a;
    border-radius: 10px;
    text-decoration: none;
}
header #newgamebtn:hover {
    background-color: #6b8b99;

}
header a {
    display: block;
}
header p {
    display: inline-block;
}
header p:nth-child(3){
   margin-right: 200px;
}
#grid-container {
    width: 460px;
    height: 460px;
    padding: 20px;
    margin: 20px auto;
    background-color: #bbada0;
    border-radius: 10px;
    position: relative;
}
.grid-cell {
    width: 100px;
    height: 100px;
    border-radius: 6px;
    background-color: #ccc0b3;
    position: absolute;
}
.number-cell {
    border-radius: 6px;
    font-family: Arial, serif;
    font-weight: bold;
    font-size: 60px;
    line-height: 100px;
    text-align: center;
    position: absolute;
}
.gameover-box {
    width: 460px;
    height: 460px;
    background-color: #bbada0;
    border-radius: 6px;
    position: absolute;
    line-height: 460px;

}
.gameover-text {
    font-family: Arial, serif;
    font-size: 64px;
    color: white;
    text-align: center;
    margin: 0 auto;

}